A variety of spectral filters are known and are used for forward-facing imagers used for vision-based based driver assistance systems (DAS) in vehicles for likes of headlamp control systems, lane monitoring systems, traffic sign detection systems and forward collision warning systems (such as those disclosed in U.S. Pat. Nos. 7,566,851; 5,796,094; 6,882,287; 5,837,994; and/or 6,291,812, and/or U.S. Pat. Publication No. US-2008/0043099, and/or International Publication No. WO 2009/046268, which are hereby incorporated by reference herein in their entireties). While such known spectral filtering works well in such DAS applications, scope exists for improvement.